Ellipsqgraph



r E; E. CLARK.

- Y ELLIPSOGRAPH; l r

, N0. 206,462. QP Lented Apr. 18, 1882*.

o af E@ if. I ABLLE I In WMV/Willmann "M .'e itk-nown that, :EZRA E. CLARK, a citi-I rzen of the UnitedStates,'residing at Worces- 4"ter, -in thecountyof Worcester and Statel of 5 Massachusetts, have inventedce'rtain newand- :i f useful Improvements-in an" Ellipsograph Vand l "Ido herebyldeelai'e the following-to be a full,

:1'-cleaipandexact*descriptionjof the in vention,

`V,such as willfenablefoffhers skilled in the art'to .l 1 o 'tvb-ich itlapper'tains tofu'lake and use the same,

reference 'being had to the ac'companyin g draw in'gs,v and@ 'to letters lor* figures of reference marked-thereonywvhich f 'ormv apart et' `this 'YThis'instrumentisdesigned fory cutting or describing ellipses,`and is applicable todraftsmens uses for drawing pencil, vink, ordottedv linlesor'gto the vWantsref,picture-tranne makers "forj cuttin g. -ovals from 1"-pasteboard,y &c., for

I zoffraines, besides-being!adapted to vvarious u'sen; .i ful-purposes inthe-arts:

' f "f'-Twoff el'erne'intar" features. are embraced in this instrum'entf'oneflbeing mechanism for causing theknife'or pen" stock Atodescribe the. 2 5 desired ellipse, andthe otherv mechanism for compelling the knife o'r pen to remain normal? 'that is, tangential" to the 'curve being vdescribed by it,inv order'that .such kliife or pen 4shall operatetorthe 'bestad\antage in cutting Theportion of theinstumentfor describing 1- the ellipse consists of two straight rods or *the other, andv crossing'at' right angles, the two rods attheir point ofY intersection being I in'closediu a common hub,l which carries thevpen-stock, and in -which-they slide independently of veach other, and each -rod being-.con- ...nectedat its ends to twin swinging parallel 40 arms orcranks, pivoted to the frame lof the instrument,xand operating to carry therods through arcs of circles of greater or less diam. eter, one pair of arms orcranksbeing. of necessity longer than Athe other, since lthe circle 4 5 'describedby one rod urust be of greater diam-A "I nalin n." CLARK, onvv'onensrnn MASSACHUSETTS. A

ELL'PSQGMPI-la I y ron reitera-gfpnt of Letters Patent No. 256,462, aatedfAprn-rs, rss2.

:application ined september 29,1881; (Monti.) A 1 Theportiou of the' instrument for maintaining the penstock normal to the curve being v'described-that is, for 'shifting the position of' such pen-stock in consonance with the change in direction lof the same-consists .inpivotng said pen-stock vertially within lthecommon y hub before named, and securing to its upper endv one end of a slotted plate orsiweep' which u straddles a stud .secured to a: longitudinal cross-head, such cross-head bein g. supported upon slide-bars playingin the upper Ipart vof the frame of thelins'trumen'and having re-f cprocatin g rectilinear movementimparted to it between the points of oscillation of the plate or sweep which supports-the pen-stock, and parallel to the longest axis of the' ellipse by a suitable Vhand-crank carrying au adjustable 'stud or Wrist-pin, whichl operates in .a groove of the head by which the -length'of motion of'7o `thecross-head' is controlled, in order that the speed of movement of said crosshead may be made to varyproportionately with the change in the curvilinear motion of the knife or pen, the combined movements ot the two being such as to maintain the said slotted plate Vor sweep, and consequently the pen or knife, norlmal to the curve being described. I The drawings accompanying this specification represent, in Figure 1, a plan, Fig. 2 an 8o under side view, and in Fig. 3 a" vertical section, of an instrument embodying myimprovey y .Y ments. bars. arranged iny horizontal planes, oneabove In the above-named drawings,A represents a square rectangular frame rcomposed of side 8 5 bars, a a a! Ia', mounted in a horizontal .plane upon suitable legs. l' -B B B2 B3frepr'esent short vertical shafts,

vmounted in bearings b, erected upon' the centers ot' the bars a a', and of course arranged in a quadrangle, each shaft'having secured to its upperand lower end one end of a crank or arm, C C or C', C', and the entire series of cranks being alwaysin parallelism'. Each lower crank,D D D' D', supports an adjustable Wrist-pin inthe form ota tubular slider or hub, E or E', and a clamp-screw, c, by which itmay be clamped to the crank, such 'screw constituting the pivot of each end of a connecting-rod, d or LQ-the rod d connecting Ico the cranks D D and the rod d the cranks D YD. Consequently these rods or bars d d' stand I -if apen'shed ink -at right angles to each other and maintain pivoted respectively to such ends as shown at g, the four sides It h h h of said frame F con stituting lbars or pitmen which unite the cranks, as shown. A suitable handle, i, is to be erected upon thetop of one of the bars h or vh by means of which the instrument is put in motion. Y v

The stock for supporting the knife, pen, or other instrument which is to describe the dcsired ellipse is shown at G as suspended from and pivoted;within a hub,1H, which has two .horizontal passages,c f, bored through it at -rightangles to each other, such passages receiving the rods d d', which are capable ofsliding freely within them. A

Each arm orerank D Dl is to have a scale of divisions-say of inches and fractions of an inchengraved upon its upper surface, for enabling the hubs E or E to be readily and accnratel'y adjusted to the desired position ac' cordiug to the size and proportions of the ellipse to be described." In the present-instance the cranks or arms D D are the longest. Hence the curved sweep described by them and their rod d carries the pen or knife through the longest sides of the ellipse, while the arms Dx i D and rod d carry the knife or pen through the shortest curves or ends of said ellipse, the

rods d d sliding with diierent rates of speed through the hub H.. Therefore it will be seen that by changing the relative positions of the Wrist-pins or hubs E E upon their cranks the size, aswell as the proportions, of the ellipse -will be varied.

To ,maintain the knife or pen normal to the l curve being described by it,in order that it a knife it may cut to the -best advantage, and most effectively, I proceed as follows:

H represents a horizontal bar or cross-head Y dsposedat the upper part ofthe frame A, and parallel to the rod d and the shortest axis of the ellipse, and supported in position upon horizontal parallel bars Vk k, which play in passages or bearings in the bars a a of the frame A, the cross-head thus supported being susceptible ofreciprocatingrectilinear movements in consonance and parallel with the rod d and between the center or points of oscillation of the plate supporting the penstock to be de scribed.

To the under side of the cross head or bar H', and centrallyof it, l affix a pendent stud or pivot, l, which enters a slot, m, in a horizontal plate or sweep, n, one end ot which is secured to the upper end ot' the pen-stock, such slotted plate or sweep being arranged at right angles to the plane of the knife or pen and adaptedto stand parallel with the rod d or d when either of such rods is parallel'with one axis of the ellipse. It is evident that if this slotted plate or sweep be maintained at right angles to the curve at every' point the knife or pen will remanin the proper position to cut or shed ink to the best advantage. The sliding carriage or cross-head H'isintroducet for this purpose, and itslength ot'lmotion must be varied with variations in the sizeof theellipse. To effect this adjustment of the cross- I head, I employ a crank or arm, o, the base of which is secured to Athelower end of a vertical shaft, p, which is supported and revolves in a nearing, q, in the center of a horizontal beam,

r, which spans centrally thctops of the bars a a ofthe frame A, and with this crank, and ad `instable upon it, I employ a tubular hub, s, provided with a clampscrew, t, for connihg it to said crank, this hub s having a pendent spur 8s or wrist-pin, u, which enters a longitudinal channel. or groovcpv, in the upper part of the cross-headlH, and operating with a scale of divisions of inches and fractions ot' an inch engraved upon the top of the arm or crank o. Furthermore, to the upper end of the` shaft p I affix the base ot an additional horizontal crank or arm, w, arranged parallel with the crank o, and having a fixed hub or wrist-pin, zr, which is pivoted to the center ofthe frame F, before mentioned.-

The relative positions of the crank o, adjustable wrist-pin or hub s, and cross-head H in relation to the pen-stock are s ueh that the sweep a andthe knife or pen,'if the huhs properly adjusted, will always be normal to the roer4 curve described by such knife or pen, and as 'the length of movement of. the cross-hea-d or carriage varies with every change in the size ofthe ellipse,a table should be provided to accompany each instrument, giving the correct distance to be set`ol on the crank o to effect the proper adjustment of the hub s. This disf tance is a ratio depending upon the two axes or diameters of the elli psc, and mayzbe expressed B In thisforby the founding formula: A.

mula, A is one-half the longest diameter and Bis one-halt` 'the shortest diameter. 4

Fig. 4 of the accompanying drawings shows a table computed for the above purpose. As an example, suppose an ellipse is wanted three and one-halt' inches long andjtwo inches wide. Preparatory to drawing or cutting such an ellipse its major axis is drawn upon the paper or other material, and the instrument placed over it in the proper position with the rod d parallel with such axis. The hubs E E are adjusted to the one and three-quarter i'nch division (which is one-half the length' of the ellipse) of the scale upon the arms D D and the'hubs E E to the one-inch division (which is one-half the width of the ellipse) ofthe scale upon the arms D D. ltecourse is now had to the table and thetnumber vat the intersection of the divisions 12 and l found, which is l inch. This is to be .laid olf on the arm or crank 0 that is to say, the hub s upon this crank is to 'be set at this division on said crank. The user now seizes the handle i, and by means of it causes the frameF to describe acomplete cir# cle, theresult bein'g that the knifeor pen is-` caused to describe an cllipseby the combined movements of the'cranks D D D/D and rods d d', acting upon tbeihub H and'pen-stock- Gr, as before explained.

I'clayim- 1. In combination with the'rectangular fram A, the cranks D D D D-,rods d d', and hubvH, tbe pivots of the rods being adjnstabllep'on the respective cranks, andthe whole being arranged to carry the stock in an elliptical'path of movement, substantially as described.

, 2. Asa means of actuating the cranks D-:D D D', the'cranks'() C'C( C,secured to the'axes of the former, and -being in their turn united by connecting-rods which compel ytb'eni' to re# Azo -tate in unison, substantially as stated.

` 3. As a means ofaccelerating or retarding the speedof rotation of the stock upon its axis to maintain the `knifeor pen normal to time curve of thefeilipse; as stated,'tiie,crossbead e H', adapted to traverse the frameA in the` same direction as the rod d', and actuated by the cranksv o and w, and the slotted plate orv arm n, aiixed at its base to` tbe stock and lstraddeling a pivotdepending from the crosslhea'd, substantiallyas herein set forth and described. .1.4,` The instrument as an entirety consisting of the frameiA, cranks C C C C D D D DC, slides or rod-sd d', connecting' rods or bars h'h h ,h of the frame F, cross-head H, with its stud or lpivot l, and adapted lto traverse the frame A, and slottedplate or arm ln,'s'tra ddling such piyotl, ,substantially-asv and forlpurposes described.l y' In testimony whereof I atlix my signature in presence of t'wdwitnesses. i y l lEZRAE.'` CLARK.

Witnesses: j r. H.` E. Loncin, b v

F. CURTIS. 

